1. Field of the Invention
This invention relates to fluid dispensers and, more particularly, to dispensers having a self-closing valve thereon.
2. Description of the Prior Art
Pouch type dispensers with self-closing valves are well known, as shown in Carlisle, U.S. Pat. No. 3,815,794, issued on June 11, 1974, wherein a spout which is flat when empty is so configured that it forms a seal thereacross when distended by contained fluid. A somewhat similar result is achieved in a dispenser having a flat spout by following the teachings of Fohr, U.S. Pat. No. 3,009,498, issued Nov. 21, 1961, wherein the ratio of width of the spout to the pouch body appears critical to establish the seal. U.S. Pat. No. 2,517,027 issued to Rado on Aug. 1, 1950 discloses still another tube-like dispensing container provided with a self-sealing aperture. The longitudinally extending neck portion at the top of the tube is narrower than the width of the tube, said neck portion being formed by a pressing and drawing action whereby its medial portion is under great elastic strain, thereby tending to resist any bending movement thereof. A slit is preferably made in the neck portion at right angles to the longitudinal dimension of the neck, whereby upon bending the neck in a direction opposite to the side of the tube where the slit is made the contents of the tube may be expelled by applying pressure to the tube walls. Such dispensers, however, have dimensional parameters which must be followed in order to have the valve action properly work and, thus, are somewhat restrictive in connection with the design of dispensing pouches. Furthermore, dispensers of the type disclosed in the patent to Rado require simultaneous bending and squeezing actions to initiate dispensing, thereby necessitating the use of both hands. Moreover, a self valving action of somethat improved reliability over that of the Carlisle, Fohr and Rado valves is desirable.
It is also known to provide a package with a nozzle which is in rolled condition when not in use and which unrolls and permits the package contents to be expressed therethrough when pressure is applied to the package. This is shown in Evras, U.S. Pat. No. 3,439,846, issued Apr. 22, 1969, in which the nozzle is described as a flat flexible tube which inherently returns to a collapsed condition and which can be aided by a spring when dense products are to be dispensed.